by Diana Campbell
Beaufort Sea – If the sea had a dinner bell, the Beaufort Sea shelf break is a ringer for one part of the Arctic food web, from plankton to whales and seabirds. That’s obvious to the people who live in Northern Alaska and the scientists who study the Beaufort Sea.
But why does this happen? What makes the area known as the Beaufort Sea shelf break, where the continental shelf ends and the deep ocean basin begins, an important feeding area for all types of Arctic marine life?
Carin Ashjian, chief scientist and a group of 19 people, mostly scientists, are aboard R/V Sikuliaq looking for those answers. Among them are people who are going to look at the physical conditions of the water and those who will look at tiny animals called zooplankton and tiny plants called phytoplankton. Others will set fish nets and see what they bring in, likely Arctic cod, a small fish loved by beluga whales. On Sikuliaq’s bridge will be people watching for whales, seals walruses and seabirds.
“We are trying to catch the mechanisms of the food chain in action,” said Ashjian, of Woods Hole Oceanographic Institution.
The crew won’t directly observe the depths of the Beaufort in an effort to understand how the wind and the water work together to produce the Beaufort buffet. Their equipment will do it for them by giving them depth, temperature and salinity. They will relate these measurements to the Arctic life they catch. They will look at the plankton and fish to see how well they are eating, how they are growing and how healthy they are.
One of the physical processes to be considered is called upwelling. Steve Okkonen, a physical oceanographer with the University of Alaska Fairbanks, said the particular upwelling the group is interested in occurs in the southern Beaufort Sea when easterly winds drive surface water to the north and deeper water moves upwards to replace it. The deep water brings zooplankton and phytoplankton towards the surface in large concentration.
“I’m like the weatherman of the ocean,” he said.
The temperatures and salinities of the sea vary at different depths. In this part of the Beaufort Sea, the water near the surface is warmer and less salty. The next layer downward is colder and increasingly salty. That’s where the plankton and copepods, tiny animals such as krill, should be. Below that layer the water warms, but is saltier still, and is the water from the Atlantic Ocean that flowed into the Arctic Ocean through Fram Strait in the eastern Arctic many years ago.
When water upwells onto the shelf, it brings the deeper water, including Atlantic water, from the Arctic Ocean up into shallower water. This deeper water contains the plankton prey of the Arctic cod, a small fish that beluga whales eat. Because there is more of their prey in the upwelled water, the group expects to find Arctic cod feeding along the shelf break during and after upwelling.
To date, the crew has recorded temperatures from the surface to about 140 meters deep or .087 miles, which have run from 41 degrees to 30 degrees. The salinity has been 26-34 PSU, or about 34 parts per thousand.
Sikuliaq is an Arctic research ship and is a floating lab and camp for the researchers. It has a main lab where microscopes, computers, specimen freezers and other equipment are used. There is an analytical lab for chemical analyses, a computer lab that is the heart of the ship’s sensors and communications equipment. The scientists will study fish in the wet lab.
Above the main deck are the science crew’s sleeping quarters and bathrooms, as well as the galley and mess hall. The ship’s crew quarters are above that deck. The top deck is the bridge, which is encircled with windows, to see most of the sea as possible. This is where the ship pilots and wildlife observers are. So far they’ve spotted some bowhead whales, a mother walrus and pup and a diversity of seabirds.
The ship is owned by the National Science Foundation and operated by the College of Fisheries and Ocean Sciences at UAF, as part of the U.S. academic research fleet. It is used by scientists in the U.S. and their international collaborators through the University-National Oceanographic Laboratory System.
The research group has spent the first week aboard Sikuliaq setting up and testing equipment. Everything is tied down, including laptops, secured by eye screws, rope and bungee cord to the plywood tables. Forest McMullen, Sikuliaq captain, said he has seen computers fly across the room and there is slim chance of recovery or repair.
The first few days at sea, Sikuliaq bobbed in a storm with 12-foot seas. Several of the scientists admit to suffering from seasickness, but have found the appropriate medicine to cope. The pitch and heaving takes a while to get used to, sort of like a roller coaster, but not as predictable.
Kate Lowry, a zooplankton phytoplankton scientist and postdoctoral scholar from WHOI, remembered how she was deathly ill for two weeks the first time she was at sea. She now takes phenergan, the medication given to pregnant women who suffer from severe morning sickness.
“I’ve never been sick on a boat since and that was 2009,” Lowry said.
During the Arctic storm, Lowry set up her zooplankton imaging and counter equipment and tested it with efficiency and a deft hand. She and the others looking at plankton collect samples from the CTD rosette, a large device with 24 plastic bottles that is able to individually take water samples at different depths. CTD stands for conductivity, temperature and depth, which the device also measures. Lowry, and others, will collect the water and filter it for the plankton. She plans to identify zooplankton through DNA. Her equipment will also take photos of the tiny sea life.
Joel Llopiz, a fish ecologist from WHOI, and his team will use a trawl net to gather fish samples. This net has a mouth that stretches out to 30 ft. by 30 ft., with 400 lb. metal doors that keep the net open and stable. The catch goes through the net and ends up in a fine mesh container.
“The fine mesh protects the catch,” explains Llopiz. Once the catch is aboard, the team begin happy job of sorting out the fish catch from the copious globs of jellyfish. Two Ph.D. students from the Joint Program between Massachusetts Institute of Technology and WHOI are sorting for fish for the first time.
“You try to pick up this thing the size of a dinner plate and your fingers go right through it,” said Chrissy Hernandez, who studies zooplankton and baby fish. “You just chuck it.”
Sikuliaq left Nome on a warm, bright Aug. 25. The ship will return with samples and data for further study back at respective universities and research centers on Sept 18.
To follow the voyage of this mission on Facebook, called Arctic Winds, Fish, Fins and Feathers, go to www.facebook.com/ArcticWFFF. On Twitter, @arctic_wfff. On Instagram, @arcticwfff. To track Sikuliaq, go to https://web.sikuliaq.alaska.edu/track/
For educators: https://www.polartrec.com/expeditions/upwelling-and-ecology-in-the-beaufort-sea.
Diana Campbell is a Communication Specialist and Research Technician for the University of Alaska Fairbanks. She is traveling aboard the Sikuliaq during its mission to study upwelling in the Beaufort Sea.